JP2005150155A - Copper foil for electromagnetic-wave shielding, its manufacturing method and electromagnetic-wave shielding body made of copper foil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a copper foil for an electromagnetic-wave shielding which has an excellent electromagnetic-wave shielding capacity and a high transmittivity and from which dust is not dropped, and to provide an electromagnetic-wave shielding body preferably used for a PDP using the copper foil. <P>SOLUTION: In the copper foil for the electromagnetic-wave shielding, a fine roughened particle layer composed of Cu or a Cu alloy is formed on at least one surface of the copper foil, and a smoothened layer composed of Co, Ni and In or these alloy is formed on the particle layer. The fine roughened particle layer in which a copper-alloy fine roughened particle layer consisting of the Cu alloy is laminated on the copper fine roughened particle layer composed of Cu is used as the particle layer, and it is preferable that the fine roughened particle layer is formed of a Cu-Co-Ni alloy. It is preferable that a rustproof treatment and a silane coupling-agent treatment are carried out on the smoothened layer of the copper foil as required and the surface of the copper foil is protected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention mainly relates to a copper foil suitable for use as an electromagnetic shield for a display, and more specifically as a material for producing an electromagnetic shield suitable for use in a plasma display panel (hereinafter sometimes referred to as PDP). The present invention relates to a copper foil and an electromagnetic wave shield made of the copper foil.

  As electronic devices such as optoelectronic components have become more sophisticated, these devices have made significant progress. Among them, displays for displaying images have been remarkably spread for television receivers, computer monitor devices, and the like. In recent years, among them, market demands for increasing the size and thickness of displays have increased, and recently, PDPs that have become large and thin have attracted attention.

  However, in principle, the PDP emits strong electromagnetic waves outside the device. Electromagnetic waves may cause damage to various instruments, and recently, electromagnetic waves also have an effect on the human body, so legal regulations regarding electromagnetic wave emission have become stricter. For example, the Electrical Appliance and Material Control Law, VCCI (Voluntary Control Council for Information by data processing equipment electronic machinery), FCC (Federal Communication Commission) and other products.

  It is essential that the electromagnetic wave shield has conductivity over the entire shield surface and is excellent in transparency. As an electromagnetic wave shield body that satisfies this requirement and has been put into practical use, there is one in which a transparent conductive thin film is disposed on the entire surface of the PDP. However, this product has a problem in transparency because the transmittance of the transparent conductive layer itself is reduced when an electromagnetic wave shielding ability of, for example, 60 dB or more is obtained.

In order to solve the above problems, a method has been proposed in which a metal fiber knitted in a mesh shape is sandwiched between a film, glass, and a polymer substrate to form an electromagnetic wave shield. However, knitting of metal fibers is likely to be kinked, and problems with appearance such as moire patterns occur when combined with a PDP.
Therefore, a method has been proposed in which a metal foil, particularly a copper foil, is bonded to a transparent polymer film using an adhesive, and then a mesh pattern is formed on the metal foil by etching. Since it becomes substantially opaque, it was a difficult task how to increase the transmittance.

On the other hand, recently, when processing a metal foil into an electromagnetic wave shield, powder fall off from the metal foil and color spots on the surface of the metal foil have been regarded as problems.
Further, in the electrolysis process for black-treating the surface of the metal foil, the use of a toxic substance such as arsenic and the use of an electrolyte solution that harms the environment has been regarded as a problem.
Research has also been conducted on electrolytic solutions excluding powder fall off from copper foil and harmful substances, and the applicant of the present application has previously disclosed a copper foil for a printed wiring board in Patent Document 1. However, the technique disclosed in Patent Document 1 is in a situation where it cannot be said that sufficient countermeasures against color tone and color spots and further powder removal are required for the electromagnetic wave shield.
JP-A-11-256389

The problem to be solved by the present invention is a plating solution that does not adversely affect the environment, and as a copper foil for electromagnetic shielding, the color tone of the black treated surface is uniform, there are no color spots, powder does not fall off, and electromagnetic shielding ability is achieved. An object of the present invention is to provide an optimal copper foil for an electromagnetic wave shielding body having excellent and high transmittance.
An object of the present invention is to provide an excellent copper foil as a material for producing an electromagnetic wave shield for PDP, and an electromagnetic wave shield that can be suitably used for a PDP produced from the copper foil.

  That is, the copper foil for electromagnetic wave shielding of the present invention is provided with a fine roughened particle layer made of Cu or Cu alloy on at least one surface of the copper foil, and Co, Ni, In or an alloy thereof on the finely roughened particle layer. A smooth layer made of is provided.

  The fine roughened particle layer may be a fine roughened particle layer obtained by stacking a copper alloy fine roughened particle layer made of a Cu alloy on a Cu fine roughened particle layer instead of the Cu or Cu alloy Cu. Good.

  The fine roughened particle layer may be formed of a Cu alloy containing Co or / and Ni.

  Further, the Cu alloy constituting the fine roughened particle layer may be a Cu alloy containing at least one of Se, Sb, W, Te, Bi, Mo, and Fe.

  The Cu alloy constituting the copper alloy fine roughened particle layer may be a Cu alloy containing at least one of Se, Sb, W, Te, Bi, Mo, and Fe.

  The smooth layer may be a Co alloy having a Cu content of 5% or less.

  The copper foil is preferably a granular crystal having a surface roughness Rz of 3 μm or less.

  The smooth layer is preferably a granular crystal having a surface roughness Rz of 3.5 μm or less.

  The method for producing a copper foil for electromagnetic shielding according to the present invention comprises providing a finely roughened particle layer of Cu or Cu alloy on at least one surface of a copper foil, and Co, Ni, In or an alloy thereof on the finely roughened particle layer. It is a manufacturing method characterized by providing the smooth layer which consists of these.

  The fine roughened particle layer is preferably plated with a copper sulfate bath.

  The smooth layer is preferably plated with a plated copper bath having a Cu content of 100 ppm or less.

  The electromagnetic wave shielding body of the present invention is an electromagnetic wave shielding body obtained by processing the copper foil for electromagnetic wave shielding produced by the method for producing the copper foil for electromagnetic wave shielding of the present invention or the copper foil for electromagnetic wave shielding of the present invention into an electromagnetic wave shielding body.

  The copper foil for electromagnetic shielding of the present invention can be formed without using an electrolytic solution that may harm the environment such as arsenic, has excellent electromagnetic shielding ability, high transmittance, uniform color tone, no color spots, and It is a copper foil for electromagnetic shielding that can be suitably used as a copper foil for electromagnetic shielding without powder falling, and further, by using the copper foil, an excellent electromagnetic shielding body that can be used for PDP and the like can be provided. It has the effect.

  In the present embodiment, the copper foil for electromagnetic wave shielding of the present invention mainly uses a rolled copper foil or an electrolytic copper foil. The copper foil for electromagnetic shielding according to the present invention is provided with one or several finely roughened particle layers of copper or copper alloy on at least one surface of an electrolytic copper foil or a rolled copper foil, or adjusts the electrolytic treatment time and current density. By adjusting the film thickness, and then providing one or several smooth layers made of Co, Ni, In or their alloys on the fine roughened particle layer, or adjusting the electrolytic treatment time and current density. The thickness is adjusted.

The reason why the finely roughened particle layer of copper or copper alloy is provided on the surface of the copper foil is to make the surface of the copper foil fine particles so that the surface is easily irregularly reflected and the reflectance is lowered.
In addition, it is preferable that the fine roughened particle layer is formed of a Cu—Co alloy, a Cu—Ni alloy, or a Cu—Co—Ni alloy because the fine roughened particle layer is easily formed into fine particles.
The thickness of the fine roughened particle layer formed of the Cu-Co alloy depends on the color required for the electromagnetic wave shield, and when a dark black color is required, it depends on the thickness of the smooth layer made of Co or the like. Increasing the number of roughened particle layers deposited or increasing the electrolysis time (thickening the thickness), if thin black is required, about 1 to 3 layers, or shortening the electrolysis time and reducing the thickness good.

The reason why the smooth layer made of Co or the like is provided in the outermost layer is to prevent the so-called powder falling phenomenon that the fine roughened particle layer falls when it comes into contact with the container or the like in the processing of the lower process.
In the copper foil for electromagnetic wave shielding of the present invention, the brightness (reflectance) and the powder falling phenomenon are related to the thickness of the smooth layer. That is, if the thickness of the smooth layer is thick, the brightness increases but the powder fall is small. Conversely, if the thickness is thin, the brightness decreases but the powder fall increases.
Further, the smooth layer made of Co or the like provided on the fine roughened particle layer affects the black shade of the copper foil surface. Therefore, the number of smooth layers or the electrolysis time (thickness) is arbitrarily selected according to the density of black, and a film thickness that meets the demand for black hue is deposited.

In the copper foil for electromagnetic shielding according to the present invention, a fine roughened particle layer is directly provided on at least one surface of the copper foil. Depending on the roughness of the copper foil surface, the copper plating is provided between the copper foil surface and the fine roughened particle layer. It is preferable to further provide a fine copper particle layer, and the surface roughness Rz of the copper foil surface is preferably 3 μm or less.
That is, a fine copper particle layer is first applied on a copper foil by copper plating. This fine copper particle layer keeps the surface roughness of the copper foil constant and, in part, has the effect of darkening the black hue even if the copper fine grained particle layer provided on it is thin. This is because it can be expected. Second, since the black color can be darkened by providing a fine copper particle layer, the thickness of the fine roughened particle layer can be reduced, and since the fine copper particle layer is the same metal as the copper foil, both In particular, a copper alloy (for example, Cu-Co alloy, Cu-Ni alloy, Cu-Co-Ni alloy) provided on the surface can be made finer and coarsened particle layer can be thinned, so that the powder fall phenomenon is reduced and the smooth layer is formed. This is because the thickness can be made thinner.

  Furthermore, various surface treatments may be performed on the smooth layer. Specifically, rust prevention treatment such as chromate treatment, pickling treatment, zinc / chromate treatment, or silane coupling agent treatment.

  The thickness of the copper foil is preferably 3 μm to 30 μm, more preferably 5 to 20 μm, still more preferably 7 to 12 μm. If it is thicker than this thickness, etching takes time, and if it is thinner than this thickness, handling of the copper foil becomes extremely difficult.

When the copper foil is used for electromagnetic wave shielding, the aperture ratio of the light transmitting portion is preferably 60% or more and 97% or less, more preferably 70% or more, and a larger aperture ratio is preferable.
The shape of the opening is not particularly limited, but a regular triangle, a regular square, a regular hexagon, a circle, a rectangle, a rhombus, and the like are aligned, and a shape that is uniformly arranged in the plane is preferable. A typical size of the opening of the light transmitting portion is in the range of one side or diameter of 100 to 300 μm. This is because when this value is too large, the electromagnetic wave shielding ability is lowered, and when it is too small, the display image is unfavorably affected.

  Moreover, as for the width | variety of the copper foil of the part which does not form an opening part, 5-50 micrometers is preferable. That is, the pitch is preferably 100 to 350 μm. This is because if the width is smaller than this width, the etching process becomes extremely difficult, and if the width is larger than this width, the image is unfavorably affected.

  The substantial sheet resistance of a copper foil having a light transmitting portion is measured by a four-terminal method using an electrode larger than the pattern by 5 times or more and having an electrode interval of 5 times or more than the repeating unit of the pattern. Can do. For example, if the shape of the opening is a square having a side of 100 μm and the metal layer has a width of 20 μm and the squares are regularly arranged, it is possible to measure by arranging electrodes of φ1 mm at intervals of 1 mm. Alternatively, the film on which the pattern is formed is processed into a strip shape, electrodes are provided at both ends in the longitudinal direction, the resistance is measured (R), the length in the longitudinal direction is a, and the length in the lateral direction is b. Then, a substantial sheet resistance can be obtained by resistance = R × b / a. The value thus measured is preferably 0.005 / □ or more and 0.5 / □ or less, more preferably 0.01 / □ or more and 0.3 / □ or less. If an attempt is made to obtain a value smaller than this value, the film becomes too thick and the opening cannot be sufficiently removed. On the other hand, if the value is larger than this value, sufficient electromagnetic wave shielding ability cannot be obtained.

  As the resin substrate to be bonded to the copper foil of the present invention, a transparent polymer film having appropriate heat resistance and transparency is preferable. Regarding the heat resistance, the glass transition temperature is at least 40 ° C. or higher, and the transparency is a light of 550 nm. The transmittance is preferably at least 80% or more.

  Transparent polymer films include polysulfone (PSF), polyethersulfone (PES), polyethylene terephthalate (PET), polymethylene methacrylate (PMMA), polycarbonate (PC), polyetheretherketone (PEEK), polypropylene (PP) And triacetylcellulose (TAC).

  A printing method or a photoresist method is used as a method for forming the light transmission portion on the copper foil for electromagnetic wave shielding. In the printing method, the mask layer is screen-printed with a printing resist material to form a pattern. In the method using a photoresist material, a photoresist material is formed on a metal foil by a roll coating method, a spin coating method, a full surface printing method, a transfer method, etc., and the resist is patterned by exposure and development using a photomask. . After the resist patterning is completed, the copper foil portion used as the opening is removed by etching, and a copper foil layer having a light transmitting portion having a desired opening shape and an opening ratio is provided.

  The surface light reflectance of the copper foil for electromagnetic wave shielding is desirably 1% or more and 50% or less. This is because when the copper foil for electromagnetic wave shielding is used as a translucent electromagnetic wave shielding body, the reflection of light hinders visibility. The reflectivity is generally an average reflectivity from 400 nm to 600 nm, but the reflectivity here is determined by representing the reflectivity of light having a wavelength of 550 nm, assuming that there is no wavelength dependency.

  The smooth layer is a smooth plating layer made of Co, Ni, In, or an alloy thereof. The reflectivity of the copper foil for electromagnetic wave shielding depends on the thickness of the fine roughened particle layer and the smooth layer, but the number of the smooth layer (thickness) for obtaining the reflectivity: 1% to 50% is particularly thick. There is no need, and a suitable range is substantially 5 nm or more and 100 nm or less. If it is thinner than this, powder fall-off cannot be prevented, and if it is more than this, the reflectivity becomes high, which is also a waste of material.

  It is also a preferable example that the surface of the copper foil not provided with the smooth layer is subjected to black treatment as a treatment for preventing reflection to obtain a copper foil blackened on both sides. The antireflection treatment can be achieved by providing a fine roughened particle layer such as copper, Co, Ni, or an alloy thereof as described above, or a black layer may be provided by a normal blackening treatment method.

  Next, the present invention will be specifically described with reference to examples. The present invention is not limited by the following examples.

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Sodium selenite: 0.015 g / l
Plating conditions
Temperature: 20 ° C
Current density: 20 A / dm ²
Treatment time: 1.5 seconds The adhesion amount of the copper fine-roughened particles plated under the above conditions to the copper foil was 5.4 mg / dm ² .

Next, a smooth layer made of Co was plated on the copper fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
Co sulfate (as Co metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
Plating conditions
Temperature: 50 ° C
Current density: 6A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 37 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper alloy fine roughened particle layer Plating bath composition Cu (as metal): 15 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
Sulfuric acid: 160 g / l
Plating conditions
Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 4.5 seconds The adhesion amount of the copper alloy fine roughened particles plated under the above conditions to the copper foil was 21.1 mg / dm ² .
Next, a smooth layer made of In was plated on the copper fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
In (as metal): 8g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 2.5
Plating conditions
Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 15 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 9.5 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 65 g / l
Sulfuric acid: 120 g / l
Plating conditions
Temperature: 50 ° C
Current density: 65 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the copper fine-roughened particles plated under the above conditions to the copper foil was 218.8 mg / dm ² .
Next, a copper alloy fine roughened particle layer made of a copper alloy was plated on the copper fine roughened particle layer.
Plating bath composition Cu (as metal): 1 g / l
Co (as metal): 8 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 3.8
Plating conditions
Temperature: 40 ° C
Current density: 15 A / dm ²
Treatment time: 3 seconds The adhesion amount of the copper alloy fine-roughened particles plated under the above conditions was Cu: 3.5 mg / dm ² and Co: 5.0 mg / dm ² .
Next, a smooth layer made of Co was plated on the copper alloy fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 2.5
Plating conditions
Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper alloy fine roughened particle layer was 24.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 65 g / l
Sulfuric acid: 120 g / l
Plating conditions
Temperature: 50 ° C
Current density: 65 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the copper fine-roughened particles plated under the above conditions to the copper foil was 218.8 mg / dm ² .
Next, a copper alloy fine roughened particle layer made of a copper alloy was plated on the copper fine roughened particle layer.
Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
pH: 2.5
Plating conditions
Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 1.2 seconds The adhesion amount of the copper alloy fine roughened particles plated under the above conditions was 5.6 mg / dm ² .
Next, a smooth layer made of Co was plated on the copper alloy fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 2.5
Plating conditions
Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper alloy fine roughened particle layer was 24.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 12 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 2 g / l
Co (as metal): 8 g / l
Ni (as metal): 8g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 3.5-4.0
Plating conditions
Temperature: 40 ° C
Current density: 40 A / dm ²
Treatment time: 2.4 seconds The composition of the alloy fine roughened particle layer plated under the above conditions was analyzed, and as a result, the actual composition mg / dm ² foil was Cu: 4.7, Co: 9.56, Ni: 8 .4.
Smooth layer formation conditions Next, a smooth layer made of Co was plated on the copper fine-roughened particle layer under the following plating conditions.
Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
Plating conditions
Temperature: 50 ° C
Current density: 4A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 32.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 12 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Sb: 0.2 g / l
W: 4 ppm
Plating conditions
Temperature: 20 ° C
Current density: 20 A / dm ²
Treatment time: 2.5 seconds The adhesion amount of the copper coarse particles plated under the above conditions to the copper foil was 9.7 mg / dm ² .
Smooth layer formation conditions Next, a smooth layer made of Co was plated on the copper fine-roughened particle layer under the following plating conditions.
Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
Plating conditions
Temperature: 50 ° C
Current density: 3A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 24.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 12 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Te: 0.02 g / l
Plating conditions
Temperature: 50 ° C
Current density: 30 A / dm ²
Treatment time: 2 seconds The adhesion amount of the copper coarse particles plated under the above conditions to the copper foil was 13.1 mg / dm ² .
Smooth layer formation conditions Next, a smooth layer made of Co was plated on the copper fine-roughened particle layer under the following plating conditions.
Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
Plating conditions
Temperature: 50 ° C
Current density: 4A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 32.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 15 g / l
Sulfuric acid: 160 g / l
Bi: 0.02 g / l
W: 4 ppm
Plating conditions
Temperature: 50 ° C
Current density: 20 A / dm ²
Treatment time: 2 seconds The adhesion amount of the copper coarse particles plated under the above conditions to the copper foil was 13.9 mg / dm ² .
Smooth layer formation conditions Next, a smooth layer made of Co was plated on the copper fine-roughened particle layer under the following plating conditions.
Plating bath composition
Co (as metal): 10 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
Plating conditions
Temperature: 50 ° C
Current density: 4A / dm ²
Treatment time: 30 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper fine-roughened particle layer was 32.2 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
Sulfuric acid: 160 g / l
Plating conditions
Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 4.5 seconds The adhesion amount of the copper coarse particles plated under the above conditions to the copper foil was 21.1 mg / dm ² .
Next, a smooth layer made of Co and Ni was plated on the fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
Co (as metal): 8 g / l
Ni (as metal): 0.5 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 4.5
Plating conditions
Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 20 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper alloy fine roughened particle layer was Co: 20.1 mg / dm ² and Ni: 0.42 mg / dm ² .

First, fine roughened particles are provided on one side of an electrolytic copper foil having a thickness of 10 μm by copper plating.
Plating conditions for copper fine roughening particle layer Plating bath composition Cu (as metal): 10 g / l
Fe (as metal): 4 g / l
Mo (as metal): 0.3 g / l
W (as metal): 0.3 ppm
Sulfuric acid: 160 g / l
Plating conditions
Temperature: 20 ° C
Current density: 50 A / dm ²
Treatment time: 4.5 seconds The adhesion amount of the copper coarse particles plated under the above conditions to the copper foil was 21.1 mg / dm ² .
Next, a smooth layer made of Cu and Co was plated on the fine roughened particle layer under the following plating conditions.
Smooth layer formation conditions Plating bath composition
Co (as metal): 8 g / l
Cu (as metal): 0.5 g / l
Ammonium sulfate: 40 g / l
Boric acid: 20 g / l
pH: 4.5
Plating conditions
Temperature: 40 ° C
Current density: 3A / dm ²
Treatment time: 20 seconds The adhesion amount of the smooth layer plated under the above conditions to the copper alloy fine roughened particle layer was Co: 18.2 mg / dm ² and Cu: 0.61 mg / dm ² .

On the smooth layer of the copper foil prepared in Examples 1 to 10, rust prevention treatment and silane coupling agent treatment were performed as necessary. The treatment method generally performed conventionally was applied to the rust prevention treatment and the silane coupling agent treatment method.
[Comparative example]

  Finely roughened particles were plated with copper on one surface of the electrolytic copper foil under the same conditions as in Examples 1, 5, and 10, and directly subjected to rust prevention treatment and silane coupling treatment without providing a smooth layer. This was designated as Comparative Examples 1, 2, and 3.

Evaluation 1 Powder-off characteristics Place the copper foil prepared in Examples 1 to 5 on a flat table with the black treated surface facing up, place the filter paper (Toyo Filter Paper No. 2) wet with water, and weight on it (Circular shape with a bottom diameter of 15 mmφ and a weight of 250 g) was placed, the filter paper was moved 15 cm, and then the presence or absence of copper powder adhering to the filter paper was examined. As a result, no occurrence of powder falling was observed in all examples.
In contrast, in Comparative Examples 1, 2, and 3, a lot of powder fallen was observed.

Evaluation 2 Shield characteristics 1
On the polyethylene terephthalate film (thickness 75 μm), the copper foil subjected to the black treatment of Examples 1 to 5 was applied to a polyester adhesive containing a cross-linking agent to 10 μm, and both were adhered. Next, a grid pattern having a grid width of 20 μm and an eye size of 150 μm × 150 μm was printed on the copper foil by screen printing using a thermosetting ink. After the ink was cured by heating at 90 ° C. for 5 minutes, the metal layer of the portion not protected by the ink was removed with an aqueous ferric chloride solution, and then the ink was removed with a solvent. In this way, a laminated body that was an electromagnetic wave shield with an aperture ratio of 75% was prepared. The average visible light transmittance of this laminate was measured and found to be 67% or more. When the sheet resistance was measured, it was possible to obtain an excellent electromagnetic wave shield at 0.11 Ω / □ or more.

Evaluation 3 Shield characteristics 2
An antireflection film was produced on a polyethylene terephthalate film (thickness: 100 μm) by coating with a fluororesin. The copper foil prepared in Examples 1 to 10 was laminated with an acrylic adhesive on the surface of the film not coated with the fluororesin. Next, an alkali development type photoresist is coated on a copper foil by a roll coating method, and after pre-baking, exposure and development are performed using a photomask to provide a lattice pattern with a lattice width of 25 μm and an eye size of 125 μm × 125 μm. After that, the part of the metal layer not protected by the resist was etched with a ferric chloride solution, and then the resist was removed in an alkaline solution. Thus, a laminate having an aperture ratio of 69% or more could be produced. When the average transmittance of visible light was measured, 65% or more was obtained. When the sheet resistance was measured, it was an excellent electromagnetic shielding sheet at 0.07 / □ or more.

As described above, when the copper foil is used for electromagnetic wave shielding, the aperture ratio of the light transmitting portion is preferably 70% or more. In the copper foil for electromagnetic shielding produced in this example, a regular triangle, a regular square, a regular hexagon, a circle, and a diamond-shaped opening window having a side or a diameter of 200 μm are uniformly etched in the plane, all light transmitting portions Can be etched to an opening ratio of 70% or more.
Moreover, as a result of measuring the substantial sheet resistance of the copper foil having the light transmitting portion opened as described above by the four-terminal method, a sheet resistance value between 0.01 / □ and 0.3 / □ was obtained. And has sufficient electromagnetic wave shielding ability.

Evaluation 4 Color spots The surface color tone and black color spots were visually evaluated. As a result, the color tone on the foil surface was uniform, and the presence of uneven color could not be found.

The copper foil for electromagnetic shielding of the present invention can be manufactured by an environmentally friendly manufacturing method since no harmful substances are used in the electrolyte composition, and the manufactured copper foil has excellent electromagnetic shielding ability, high transmittance, and powder falling off, There is no color spot on the surface, and it has an excellent effect that can be suitably used as a copper foil for electromagnetic wave shielding. Furthermore, by using the copper foil, it is possible to provide a good electromagnetic wave shielding body that can be used for PDP. It has excellent effects such as being possible.

Claims (14)

A fine roughened particle layer made of Cu or Cu alloy is provided on at least one surface of the copper foil, and a smooth layer made of Co, Ni, In or an alloy thereof is provided on the fine roughened particle layer. A copper foil for electromagnetic wave shielding. The fine roughening particle layer is a fine roughening particle layer in which a copper alloy fine roughening particle layer made of a Cu alloy is laminated on a copper fine roughening particle layer made of Cu. The copper foil for electromagnetic wave shielding of 1. The copper foil for electromagnetic wave shielding according to claim 1, wherein the fine roughened particle layer is a Cu alloy containing Co or / and Ni. 2. The copper foil for electromagnetic wave shielding according to claim 1, wherein the fine roughened particle layer is a Cu alloy containing at least one of Se, Sb, W, Te, Bi, Mo, and Fe. The copper foil for electromagnetic wave shielding according to claim 2, wherein the copper alloy fine roughened particle layer is a Cu alloy containing at least one of Se, Sb, W, Te, Bi, Mo, and Fe. . The copper foil for electromagnetic wave shielding according to any one of claims 1 to 5, wherein the smooth layer is a Co alloy having a Cu content of 5% or less. The copper foil for electromagnetic wave shielding according to claim 1, wherein the copper foil is a granular crystal having a surface roughness Rz of 3 μm or less. The copper foil for electromagnetic wave shielding according to any one of claims 1 to 7, wherein the smooth layer has a surface roughness Rz of 3.5 µm or less. The copper foil for electromagnetic wave shielding according to any one of claims 1 to 8, wherein an antirust treatment is applied on the smooth layer. The copper foil for electromagnetic wave shielding according to any one of claims 1 to 8, wherein a treatment with a silane coupling agent is performed on the smooth layer. A copper or Cu alloy fine roughened particle layer is provided on at least one surface of the copper foil, and a smooth layer made of Co, Ni, In or an alloy thereof is provided on the fine roughened particle layer. A method for producing a copper foil for electromagnetic wave shielding. The method for producing a copper foil for electromagnetic wave shielding according to claim 11, wherein the fine roughened particle layer is plated with a copper sulfate bath. The method for producing a copper foil for electromagnetic wave shielding according to claim 11, wherein the smooth layer is plated with a plated copper bath having a Cu content of 300 ppm or less. An electromagnetic wave shielding body, wherein the electromagnetic shielding copper foil according to any one of claims 1 to 13 is processed into an electromagnetic wave shielding body.